Question

An object is dropped off a building that us 144 feet tall. After how many seconds does the object hit the ground? (s= 16t^2)

Answer 1

Given
s=16t^2
where
s=distance in feet travelled (downwards) since airborne with zero vertical velocity and zero air-resistance
t=time in seconds after release

Here we're given
s=144 feet
=>
s=144=16t^2
=>
t^2=144/16=9
so
t=3
Ans. after 3 seconds, the object hits the ground 144 ft. below.

Answer 2

After 3 seconds the object hit the ground.

Explanation:

An object is dropped off a building that us 144 feet tall. After how many seconds does the object hit the ground.

Given that displacement, s = 16t²

To reach ground displacement should be 144 feet.

That is

s = 16t² = 144

t² = 9

t = 3 seconds.

After 3 seconds the object hit the ground.